Biomarker testing in patients (pts) with metastatic colorectal cancer (mCRC): Perspectives from U.S. oncologists (ONC) in rural areas and urban clusters

ABSTRACT

Background: In the US, pts living in rural areas have higher CRC mortality rates than urban areas. Clinical guidelines recommend testing for BRAF and RAS mutations and deficient mismatch repair/microsatellite instability in pts with mCRC. However, data on biomarker testing rates in rural communities compared with urban areas are limited. We surveyed ONC in the US who practice in rural areas or urban clusters to identify biomarker testing patterns and barriers (data previously reported) and conducted interviews with a select group of respondents to further understand key differences that may contribute to substandard biomarker testing rates in rural areas. Methods: A 2-part (quantitative and qualitative) survey was conducted with ONC who spend > 40% of their time providing direct care to pts in rural areas or urban clusters and who had treated ≥2 pts with stage IV mCRC in the month prior to the survey. After screening, a subset of those who completed the quantitative survey participated in the qualitative survey (a 30- minute, web-assisted, telephone interview). The interview questions targeted 6 areas clinical practice description, biomarker and genomic testing patterns, pathology and molecular tumor board, tumor tissue journey, electronic health records, and training/educational opportunities. Results: Of the 99 ONC who responded to the quantitative survey, 17 were interviewed for the qualitative survey from June 16-29, 2021. A key finding of the quantitative survey was that although ONC reported being familiar with biomarkers relevant to mCRC, the reported rate of biomarker testing was suboptimal. The interviews probed reasons why testing does not align with current guidelines and found that challenges exist throughout the tumor tissue journey including insufficient tumor tissue available for testing (especially in the relapsed/refractory setting);lack of or limited protocols, clinical decision support systems, reflexive testing, and molecular tumor boards;lengthy and difficult-to-navigate next-generation sequencing reports;and financial toxicity surrounding biomarker tests (especially for underinsured pts), among other barriers. Despite these challenges, ONC reported easy access to third-party reference labs and electronic references, such as NCCN and UpToDate. Although telehealth visits have nearly quadrupled during the COVID pandemic, access to telehealth may be limited for pts living in rural areas or urban clusters. Conclusions: The ONC surveyed reported that practicing in rural/urban clusters poses unique challenges related to tissue acquisition, practice resources, pts' ability to pay, and clinical knowledge gaps that may affect biomarker testing rates in pts with mCRC. Addressing these gaps is warranted if optimal utilization of precision medicine tools is to be realized.